原标题：Linear LTC3856多相同步降压电源转换方案

　　Linear 公司的LTC3856是但输出双路多相同步降压DC/DC控制器,能驱动所有的N沟功率MOSFET,输入电压从4.5V到38V,基准电压0.6V,精度±0.75%,可锁相的固定频率从250kHz到770kHz,可编程的突发模式或级屏蔽,以获得轻负载的最大效率.效率高达95%.主要用在电信和数据通信,工业和医疗设备,DC电源分布系统和计算机系统.本文介绍了LTC3856主要特性,方框图,采用电阻和电感DCR检测电流的电路图,以及典型应用电路图和1.5V/50A转换器电路图.

　　Linear 公司的LTC3856是但输出双路多相同步降压DC/DC控制器,能驱动所有的N沟功率MOSFET,输入电压从4.5V到38V,基准电压0.6V,精度±0.75%,可锁相的固定频率从250kHz到770kHz,可编程的突发模式或级屏蔽,以获得轻负载的最大效率.效率高达95%.主要用在电信和数据通信,工业和医疗设备,DC电源分布系统和计算机系统.本文介绍了LTC3856主要特性, 方框图, 采用电阻和电感DCR检测电流的电路图,以及典型应用电路图和1.5V/50A转换器电路图.

　　The LTC®3856 is a single output, dual channel PolyPhase synchronous step-down DC/DC controller that drives all N-channel power MOSFET stages. This device includes a high speed differential amplifier for remote output volt­age sense. Power loss and supply noise are minimized by operating the two controller output stages out-of-phase and up to 12-phase operation can be achieved.

　　The LTC3856 monitors the output current by sensing the voltage drop across the output inductor (DCR) or by using a sense resistor. DCR temperature compensation maintains an accurate current sense threshold over a broad temperature range. A constant-frequency, current mode architecture allows a phase-lockable frequency of up to 770kHz.

　　A wide 4.5V to 38V input supply range encompasses most intermediate bus voltages and battery chemistries. Burst Mode operation, continuous or Stage Shedding modes are supported. A TK/SS pin shared by both chan­nels ramps the output voltage during start-up.

　　LTC3856主要特性:

　　PolyPhase® Controller Reduces Input and Output Capacitance and Power Supply Induced Noise

　　Wide VIN Range: 4.5V to 38V Operation

　　±0.75%, 0.6V Reference Voltage Accuracy

　　High Efficiency: Up to 95%

　　Programmable Burst Mode® Operation or Stage Shedding™ for Highest Light Load Efficiency

　　Active Voltage Positioning (AVP)

　　RSENSE or DCR Current Sensing

　　Programmable DCR Temperature Compensation

　　Phase-Lockable Fixed Frequency: 250kHz to 770kHz

　　True Remote Sense Differential Amplifier

　　Dual N-Channel MOSFET Synchronous Drive

　　VOUT Range: 0.6V to 5V without Differential Amplifier

　　VOUT Range: 0.6V to 3.3V with Differential Amplifier

　　Adjustable Soft-Start or VOUT Tracking

　　Stackable for Up to 12-Phase Operation

　　32-Pin (5mm × 5mm) QFN and 38-Pin TSSOP Packages

　　LTC3856应用:

　　Telecom and Datacom Systems

　　Industrial and Medical Instruments

　　DC Power Distribution Systems

　　Computer Systems

　　图1.LTC3856方框图

　　图2.LTC3856采用电阻检测电流电路图

　　图3.LTC3856采用电感DCR检测电流电路图

　　图4.LTC3856典型应用电路图

　　图5.LTC3856采用电阻检测的1.5V/50A转换器电路图